Did this sort of thing really happen? Motor melt down question

[bad Chad]

Was watching Ride the other night,  they where talking to an old boy former moonshine runner.

This guy claimed that in the 70s he was being chased by a cop up the mountain.  The were of course running very hard and at some point they stopped the cars.  The trooper turned off his Ford, and when he went to start it up again, the pistons had melted to the cylinders.

Did that sort of thing actually happen?

[redrider]

Saw it Meself. I suppose it is possible. Shut off your car engine and turn the key on, watch the temp gauge climb. Cooling those old iron blocks was not uniform and running hard generated really hot hot spots.

[charlie b]

Pistons probably not melted to cylinders, but, could have seized after shutdown and cooling.  Have had that happen to me with a VW.  It was showing signs of distress when I turned it off  :)

[rocker59]

  The were of course running very hard and at some point they stopped the cars.  The trooper turned off his Ford, and when he went to start it up again, the pistons had melted to the cylinders.

Did that sort of thing actually happen?

Nah.  the pistons don't get hot enough to melt.  If combustion temps don't melt the pistons, sitting parked and turned off  after a long run won't.

More likely, the car was run for a long period in a state of over-heating, which might cause the engine to seize from a variety of causes other than melting pistons.

Or, the guy was just bullshitting you.

[pete mcgee]

Doubt it.
Rocker nailed it.
Melting point for pure aluminium is over 600 deg c
Melting point for the alloy used in pistons is over 700 deg c.
It is possible to get those temps during lean mixture combustion, turn off the ignition and you will have the latent heat from the block which won't be that high.
Other issues like oil breakdown, ie never had oil / oil filter changed regularly, detonation, cooling system failure etc will allow damage if things aren't within normal spec.

Cheers

[lucydad]

Often wondered about engine "melt" on three cylinder, two-stroke snowmobile and motorcycle air cooled engines.  Examples are Kawasaki Mach III and Rotax free air triples.  Saw a couple Ski-Doo blizzard engines break rods--and run terrible and such.  I am no expert--heard middle cylinder on the Kawasakis was often prone to "issues".  Where is Triple Jim? 

Dang those engines ran hot.  We used to limit idling.  Ran best at zero degrees, and like crap, with vapor lock common above 30F.  Rotate, free air triple 650s and 797.  Incredible machines with tuned triple carbs and triple expansion chambers.  Still can't hear well from right ear.  Would give a lot for one more ride on a Blizzard 797 at Stoner Pass, CO in January with six feet of snow....

https://www.youtube.com/watch?v=XFBCQF2hw4Y

[Penderic]

Good use for that hot motor!




Yum Yum. You keep the bacon and sausages hot on the back burner.


And nothing looks better than fresh made biscuits under bugfree glass. Salute!


Now we're cooking! Its Leadfree for me and a doubleshot of ethanol for the driver.





Wait! Don't forget about us bikers!


 

[Motu]

For a piston to seize, it has  melted.  Heat soak can boil an engine, and coke the oil in a turbo.  Seizing is extreme, but very possible.

[Old Jock]

Like the Kwacker Triples, Triumph Tridents were prone to melting a hole in the piston of the middle cylinder

Been there.............. ..............when it happens the symptoms are loss of power and the mirrors go a bluey grey colour

[Rough Edge racing]

  There's a complex relationship between air fuel ratios and engine/combustion chamber temperatures....The lean condition can lead to preignition...It's preignition burns nice net holes in pistons...Too much spark advance at wide open throttle and or low octane fuel can lead to preignition even if the fuel mixture is correct.  Actual combustion chamber temperatures are hottest at 14.7 fuel mixture because all the fuel is being burned.....Chamber temperature tend to go down when the mixture is leaned or richened in relation to 14.7 during less than full throttle operation...At maximum power the air fuel mixture is around 12-1....Run an engine wide open at the "ideal" 14.7 air fuel mixture and preignition will burn holes or detonation will break the rings....At light throttle an engine can be happy on 16-1 air fuel mixture if it doesn't have a three way catalytic convertor....